Liquid crystal display device and electronic apparatus

ABSTRACT

In a liquid crystal display device, a reflecting surface is attached to a portion, which overlaps with a periphery portion of a light guiding plate where the light incident section is position in a surface on the light guiding plate side in the dispersing sheet which is positioned farthest to the light guiding plate side among a plurality of optical sheets which are positioned between the light guiding plate and a liquid crystal panel. As a result, light which is emitted from the periphery portion of the light guiding plate is returned into the light guiding plate by being reflected by the reflecting surface, and after this, is emitted as illumination light from a light emitting surface while progressing within the light guiding plate.

This is a continuation application of application Ser. No. 13/548,566filed Jul. 13, 2012, which claims priority to JP 2011-157592 filed Jul.19, 2011. The disclosures of the prior applications are herebyincorporated by reference herein in their entirety.

BACKGROUND

1. Technical Field

The present invention relates to a liquid crystal display device whichis provided with a light guiding plate, a light source, and a liquidcrystal panel and an electronic apparatus which is provided with theliquid crystal display device.

2. Related Art

Among the various types of display devices, a liquid crystal deviceprovided with a transparent type of liquid crystal panel has a lightguiding plate and a li/ght source where a light emitting surface isdirected toward a side edge surface which is a light incident section ofthe light guiding plate. The liquid crystal panel is arranged to overlapwith the light emitting surface of the light guiding plate. In such aliquid crystal display device, after being incident from the side edgesurface (light incident section) of the light guiding plate, the lightwhich is emitted from the light source is emitted as illumination lightfrom a light emitting surface while progressing within the light guidingplate and is modulated using the liquid crystal panel. In addition,between the liquid crystal panel and the light guiding plate, an opticalsheet such as a diffusing sheet or a prism sheet is arranged so as tooverlap and the uniformity of the intensity of the illumination lightand the like is increased using the optical sheet.

In addition, a technique is proposed where a reflecting member with arectangular frame shape is arranged between the diffusing sheet and theliquid crystal panel, leaking of light is prevented, and light which isto leak is incident in the light guiding plate and is used asillumination light (JP-A-11-149254).

In addition, a technique is proposed where a reflecting member which isseparate to the optical sheet is provided at a position which overlapswith the light source at the side of the optical sheet, leaking of lightis prevented, and light which is to leak is incident in the lightguiding plate and is used as illumination light (JP-A-2009-38006 andJP-A-2003-270634).

However, as in JP-A-11-149254, in a case where the reflecting memberwith a rectangular frame shape is added between the optical sheet suchas the diffusing sheet and the liquid crystal panel, there is a problemin that it takes time and effort to assemble the liquid crystal displaydevice since it is necessary to provide the reflecting member whilebeing careful so that the reflecting member does not extend out from theimage display region of the liquid crystal panel. In addition, there isa concern that, even if the reflecting member is appropriately arrangedduring assembly, the reflecting member may be shifted and extend outfrom the image display region after assembly. Furthermore, when thereflecting member is arranged between the optical sheet and the liquidcrystal panel in a case where a plurality of optical sheets arearranged, there is a problem in that the light which is reflected by thereflecting member passes through the optical sheets and significantlyattenuates while returning in the light guiding plate and it is hardlypossible to use any of the light as illumination light.

In addition, as in JP-A-2009-38006 and JP-A-2003-270634, considerabletime and effort is taken in the arranging of the reflecting member in aconfiguration where the reflecting member which is separate to theoptical sheet is provided to overlap with the light source at the sideof the optical sheet. In addition, even if the light which is to leak isincident on the light guiding plate by being reflected at the reflectingmember which overlaps with the light source, it is difficult for thelight to be emitted as illumination light from the light emittingsurface while progressing in the light guiding plate since the incidentangle of the light toward the light guiding plate is extremely small.

SUMMARY

An advantage of some aspects of the invention is that there is provideda liquid crystal display device, which is able to use light which is toleak as illumination light by being returned in the light guiding platewithout increasing the number of processes in assembly, and anelectronic apparatus which is provided with the liquid crystal displaydevice.

According to an aspect of the invention, there is provided liquidcrystal display device including: a light guiding plate that has aplurality of edge surfaces; a light source that has a light emittingsurface, the light source emits a light from the light emitting surface,the light emitted by the light source entering a first edge surface ofthe plurality of edge surfaces; and a liquid crystal panel which isarranged to overlap with a second edge surface of the plurality of edgesurfaces from which the light emitted by the light source comes out; aoptical sheet which is disposed between the liquid crystal panel and thelight guiding plate, the optical sheet having a reflecting surfacepositioned at least at a periphery portion of the optical sheet which iscorresponding side to the first edge surface.

According to the aspect of the invention, the reflecting surface isattached to the portion which overlaps with a periphery portion on aside where the light incident section of the light guiding plate ispositioned in light guiding plate side of the optical sheet which ispositioned farthest to the light guiding plate side among the pluralityof optical sheets which are positioned to overlap each other between thelight guiding plate and the liquid crystal panel. As a result, lightwhich is emitted from the periphery portion of the light guiding plateis returned into the light guiding plate by being reflected at thereflecting surface, and after this, is emitted as illumination lightfrom the light emitting surface while progressing in the light guidingplate. In addition, attenuation until the light which is reflected atthe reflecting surface is returned in the light guiding plate is smallsince the reflecting surface is attached to light guiding plate side ofthe optical sheet which is positioned farthest to the light guidingplate side. Accordingly, according to the aspect of the invention, theefficiency where it is possible to use the light which is emitted fromthe light source as illumination light is high. In addition, thereflecting surface is also positioned if light guiding plate side of theoptical sheet is positioned since the reflecting surface is attached tolight guiding plate side of the optical sheet. Accordingly, different tothe case where the reflecting member which is a separate body is used,the number of processes is not increased during assembly of the liquidcrystal display device even if the reflecting surface is added.Furthermore, if at the optical sheet on the light guiding plate, it ispossible to efficiently perform the process where the reflecting surfaceis provided compared to the light guiding plate.

It is preferable that the reflecting surface be attached to a surface onthe light guiding plate side of light guiding plate side of the opticalsheet. According to such a configuration, it is not necessary for thelight which is reflected at the reflecting surface to pass through theoptical sheet when returning into the light guiding plate since theoptical sheet is not interposed between the reflecting surface and thelight guiding plate. Therefore, it is possible to suppress theattenuation until the light which is reflected at the reflecting surfaceis returned in the light guiding plate to a minimum.

It is preferable that two side edge surfaces which oppose each other inthe light guiding plate be the light incident sections and thereflecting surface be attached to a portion which overlaps with theperiphery portion on both sides of the light guiding plate in lightguiding plate side of the optical sheet.

It is preferable that the reflecting surface be formed from a reflectinglayer which is formed onto the optical sheet.

In this case, it is preferable that the thickness of the reflectinglayer be thinner than the thickness of the optical sheet. According tosuch a configuration, it is possible to prevent considerable warping ofthe optical sheets when the optical sheets are arranged to overlap evenif the reflecting layer is provided.

It is preferable that the reflecting layer be formed from a layer whichis white.

It is preferable that the reflecting layer be formed from a layer whichhas glossiness. In this case, it is possible to adopt a configurationwhere the reflecting layer is formed from a metal layer.

It is preferable that the reflecting layer be formed from a coatingfilm, a transcription film, a sputtering film, a deposition film, and amember with a sheet shape.

It is preferable that the reflecting surface be formed from a smoothsurface on light guiding plate side of the optical sheet. According tosuch a configuration, it is not necessary to laminate the reflectinglayer onto light guiding plate side of the optical sheet since theboundary of the smooth surface on the optical sheet itself on the lightguiding plate side and a layer of air functions as the reflectingsurface. In addition, it is possible to prevent considerable warping ofthe optical sheets when the optical sheets are arranged to overlap.

According to another aspect of the invention, there is provided anelectronic apparatus such as a liquid crystal television including theliquid crystal display device according to the aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIGS. 1A and 1B are explanatory diagrams of a liquid crystal television(an electronic apparatus) which is provided with a liquid crystaldisplay device according to a first embodiment of the invention.

FIGS. 2A and 2B are explanatory diagrams illustrating an overallconfiguration of the liquid crystal display device according to thefirst embodiment of the invention.

FIG. 3 is an exploded perspective diagram where there is a furtherbreakdown of the liquid crystal display device according to the firstembodiment of the invention.

FIGS. 4A and 4B are cross-sectional diagrams of the liquid crystaldisplay device according to the first embodiment of the invention.

FIGS. 5A and 5B are explanatory diagrams illustrating a configuration ofthe surroundings of a light source substrate which is used in anillumination device of the liquid crystal display device according tothe first embodiment of the invention.

FIGS. 6A and 63 are explanatory diagrams of a main portion of the liquidcrystal display device according to the first embodiment of theinvention.

FIGS. 7A and 7B are explanatory diagrams of a main portion of a liquidcrystal display device according to a second embodiment of theinvention.

FIGS. 8A and 83 are explanatory diagrams of a main portion of a liquidcrystal display device according to a third embodiment of the invention.

FIGS. 9A and 9B are explanatory diagrams of a main portion of a liquidcrystal display device according to a fourth embodiment of theinvention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments where the invention has been applied to a liquid crystaldisplay device for a liquid crystal television will be described withreference to the diagrams. Here, the scale for each layer and eachmember differs in the diagrams which are referenced in the descriptionbelow in order that each layer and each member is a size to the extentthat recognition is possible in the diagram. In addition, in thedescription below, the directions which intersect each other in thedirection of the surface of the light guiding plate and the liquidcrystal panel are the X axial direction and the Y axial direction andthe direction which is orthogonal to the X axial direction and the Yaxial direction is the Z axial direction. In addition, in the diagramswhich are referenced below, one side in the X axial direction is X1 sideand the other side is X2 side, one side in the Y axial direction is Y1side and the other side is Y2 side, and one side in the Z axialdirection is Z1 side (lower side) and the other side (the side where theillumination light and the display light is emitted) is Z2 side (upperside).

First Embodiment

Overall Configuration

FIGS. 1A and 1B are explanatory diagrams of a liquid crystal television(an electronic apparatus) which is provided with a liquid crystaldisplay device according to a first embodiment of the invention andFIGS. 1A and 1B are an explanatory diagram schematically illustrating anouter appearance of a liquid crystal television and a block diagramillustrating an electrical configuration of the liquid crystal displaydevice.

An electronic apparatus 2000 illustrated in FIG. 1A is a liquid crystaltelevision and has a liquid crystal display device 100, a frame 2010 fora television, and the like. The liquid crystal display device 100 has aliquid crystal panel 10 which will be described later, an image signalsupply section 270 which supplies an image signal to the liquid crystalpanel 10, and an illumination device 8 which supplies illumination lightto the liquid crystal panel 10. In addition, the liquid crystal displaydevice 100 has a scanning line driving circuit 104 which drives ascanning line which extends in the X axial direction in the liquidcrystal panel 10 and a data line driving circuit 101 which drives a dataline which extends in the Y axial direction in the liquid crystal panel10. In regard to the scanning line driving circuit 104 and the data linedriving circuit 101, it is possible to adopt a configuration where bothare embedded in the liquid crystal panel 10. In addition, it is possibleto adopt a configuration where one among the scanning line drivingcircuit 104 and the data line driving circuit 101 is embedded in theliquid crystal panel 10 and the other is embedded in a driving IC whichis COG mounted in the liquid crystal panel 10. In addition, it ispossible to adopt a configuration where one among the scanning linedriving circuit 104 and the data line driving circuit 101 is embedded inthe liquid crystal panel 10 and the other is embedded in a driving ICwhich is mounted in a circuit substrate which is electrically connectedto the liquid crystal panel 10. Furthermore, it is possible to adopt aconfiguration where both of the scanning line driving circuit 104 andthe data line driving circuit 101 are embedded in a driving IC which isa separate body to the liquid crystal panel 10.

In the embodiment, the illumination device 8 has a light guiding plate80 which is arranged to overlap with the liquid crystal panel 10, aplurality of light emitting elements 89 which are arranged along theside edge surface which is a light incident section 80 a among the sideedge surfaces of the light guiding plate 80, a light source substrate 88where the plurality of light emitting elements 89 is mounted, and alight source driving section 280 which drives the light emittingelements 89. In the embodiment, the liquid crystal panel 10 is aquadrangle shape and has four sides 10 a, 10 b, 10 c, and 10 d. Amongthe sides 10 a, 10 b, 10 c, and 10 d, the side 10 a is a long side whichis positioned on one side Y1 in the Y axial direction, the side 10 b isa long side which is positioned on the other side Y2 in the Y axialdirection, the side 10 c is a short side which is positioned on one sideX1 in the X axial direction, and the side 10 d is a short side which ispositioned on the other side X2 in the X axial direction. To correspondwith such a formation, the light guiding plate 80 has four side edgesurfaces 801, 802, 803, and 804. Among the side edge surfaces 801 to804, the side edge surface 801 is positioned on the long side on oneside Y1 in the Y axial direction, the side edge surface 802 ispositioned on the long side on the other side Y2 in the Y axialdirection, the side edge surface 803 is positioned on the short side onone side X1 in the X axial direction, and the side edge surface 804 ispositioned on the short side on the other side X2 in the X axialdirection. In the embodiment, among the four side edge surface 801, 802,803, and 804 of the light guiding plate 80, the two side edge surfaces801 and 802 which are opposed in the short side direction (the Y axialdirection) are the light incident sections 80 a. As a result, the lightemitting elements 89 are arranged along the two side edge surfaces 801and 802 (the light incident sections 80 a) of the light guiding plate 80and the light source substrate 88 extends along the two side edgesurfaces 801 and 802 (the light incident sections 80 a) of the lightguiding plate 80.

Specific Configuration of Liquid Crystal Display Device 100

FIGS. 2A and 2B are explanatory diagrams illustrating an overallconfiguration of the liquid crystal display device 100 according to thefirst embodiment of the invention. FIGS. 2A and 2B are a perspectivediagram and an exploded perspective diagram of the liquid crystaldisplay device 100. FIG. 3 is an exploded perspective diagram wherethere is a further breakdown of the liquid crystal display device 100according to the first embodiment of the invention. FIGS. 4A and 4B arecross-sectional diagrams of the liquid crystal display device 100according to the first embodiment of the invention. FIGS. 4A and 4B area cross-sectional diagram when the liquid crystal display device 100 iscut along a line IVA-IVA of FIG. 1A and a cross-sectional diagram whenthe liquid crystal display device 100 is cut along a line IVB-IVB ofFIG. 1A.

In FIGS. 2A to 4B, the liquid crystal display device 100 of theembodiment is typically provided with the illumination device 8 which isreferred to as a so-called back lighting device and the liquid crystalpanel 10 which is a transparent type which is arranged to overlap withthe upper surface of the illumination device 8. In the liquid crystaldisplay device 100, the illumination device 8 is provided with a firstframe 40 (lower metal frame) made from metal which is arranged to coverthe rear surface of the light guiding plate 80 at a lower side (one sideZ1 in the Z axial direction), a second frame 30 (resin frame) made ofresin which holds the edge portion of the liquid crystal panel 10 abovethe first frame 40 and holds by surrounding the illumination device 8,and a third frame 50 (upper metal frame) made from metal which isarranged in the upper surface of the second frame 30 (the other side Z2in the Z axial direction).

The second frame 30 has a rectangular frame shape which holds the edgeportion of the liquid crystal panel 10 and surrounds the outside of theliquid crystal panel 10, and in the embodiment, the second frame 30 isformed from four frame plates 31, 32, 33, and 34 which are partitionedinto each of the four sides of the liquid crystal panel 10. In theembodiment, the second frame 30 is black and prevents the generation ofstray light in the illumination device 8 by functioning as a lightabsorption member. The frame plates 31, 32, 33, and 34 are respectivelyprovided with side plate sections 311 to 341 which extend downward atthe outer surface side of the frame plates 31, 32, 33, and 34, upperplate sections 315, 325, 335 and 345 (edge plate sections) which arebent toward the inner side from the upper edge of the side platesections 311, 321, 331, and 341, and protruding plate sections 312, 322,332, and 342 which extend to the inner side from an intermediateposition in the height direction of upper plate sections 315, 325, 335,and 345. As a result, step sections 313, 323, 333, and 343 are formeddue to the protruding plate sections 312, 322, 332, and 342 at the innerside of the frame plates 31 to 34 and the liquid crystal panel 10 isheld by the step sections 313, 323, 333, and 343 and the protrudingplate sections 312, 322, 332, and 342. In addition, the light guidingplate 80, the light emitting elements 89, and the like of theillumination device 8 are arranged at the lower side of the protrudingplate sections 312, 322, 332, and 342.

The first frame 40 is formed by press processing or the like with regardto a metal plate which is thin such as an SUS plate. The first frame 40is provided with a bottom plate section 45 and three side plate sections42 to 44 which rise up from three sides excluding the one side Y1 in theY axial direction among the outer periphery edge of the bottom platesection 45 and is a rectangular box shape where the upper surface isopen. The side plate sections 321, 331, and 341 of the second frame 30overlap at the outer side of the side plate sections 42 to 44 of thefirst frame 40. In addition, the side plate section 311 of the secondframe 30 covers the one side Y1 in the Y axial direction of the firstframe 40.

In the same manner as the first frame 40, the third frame 50 is alsoformed by press processing or the like with regard to a metal platewhich is thin such as an SUS plate. The third frame 50 is provided witha rectangular upper plate section 55 (edge plate section) and four sideplate sections 51 to 54 which are curved downward from the outerperiphery edge of the upper plate section 55 and is a rectangular boxshape where the lower surface is open. The side plate sections 51 to 54overlap by covering the outer side of the side plate sections 311, 321,331, and 341 of the second frame 30. A rectangular window 550, wherelight which is emitted from the liquid crystal panel 10 is emitted, isformed in the upper plate section 55 and the upper plate section 55covers the outer periphery edge section over the entire periphery amongthe display light emitting side of the liquid crystal panel 10. Inaddition, at the same time, the upper plate section 55 of the thirdframe 50 is set to completely cover above the upper plate sections 315,325, 335, and 345 (edge plate sections) of the second frame 30.

The third frame 50, the second frame 30, and the first frame 40 whichare configured in this manner are combined using screws (not shown) orthe like and hold the liquid crystal panel 10 and the illuminationdevice 8 at the inner side. Here, flexible sheets 91 and 92 are bondedto the lower surface and the upper surface of the protruding platesections 312, 322, 332, and 342 of the second frame 30 as shown in FIGS.4A and 4B. As a result, when the liquid crystal display device 100 isbeing assembled, the liquid crystal panel 10 is supported by theprotruding plate sections 312, 322, 332, and 342 via the flexible sheet92. In addition, when the liquid crystal display device 100 is beingassembled, the optical sheet (a dispersion sheet 182, prism sheets 183and 184, and the like) of the illumination device 8 are pressed so thatlifting or positional deviation does not occur through the flexiblesheet 91.

Configuration of Liquid Crystal Panel 10

As shown in FIGS. 2A to 4B, the liquid crystal panel 10 has a planarform with a quadrangle shape and is provided with an element substrate11 where a pixel electrode (not shown) or the like is formed, anopposing substrate 12 which is arranged so as to oppose via apredetermined gap with regard to the element substrate 11, and a sealmaterial 14 with a rectangular frame shape which bonds the opposingsubstrate 12 and the element substrate 11. A liquid crystal layer 13 isheld in a region which is surrounded by the seal material 14 in theliquid crystal panel 10. The element substrate 11 and the opposingsubstrate 12 are formed from transparent substrates such as glasssubstrates. In the element substrate 11, while a plurality of scanninglines (not shown) extend in the X axial direction, a plurality of datalines (not shown) extend in the Y axial direction and switching elements(not shown) and pixel electrodes (not shown) are provided to correspondto the intersections of the scanning lines and the data lines.

In the embodiment, the opposing substrate 12 is arranged on the emittingside of the display light and the element substrate 11 is arranged onthe side of the illumination device 8. In addition, in the opposingsubstrate 12, a frame edge layer 120 formed from a light blocking layerwith a rectangular frame shape is formed along the inner edge of thefour sides of the seal material 14 in the surface which opposes theelement substrate 11 and the region which is specified by the inner edgeof the frame edge layer 120 is an image display region 100 a. Here, theinner edge of the upper plate section 55 of the third frame 50 is in anintermediate position in the width direction in the frame edge layer 120and the window 550 of the third frame 50 overlaps with the image displayregion 100 a and the inner edge portion of the frame edge layer 120.

The liquid crystal panel 10 is configured as a liquid crystal panel witha TN (Twisted Nematic) method, an ECB (Electrically ControlledBirefringence) method, or a VAN (Vertical Aligned Nematic) method, apixel electrode is formed in the element substrate 11, and a commonelectrode (not shown) is formed in the opposing substrate 12. Here, in acase where the liquid crystal panel 10 is a liquid crystal panel with anIPS (In Plane Switching) method or a FFS (Fringe Field Switching)method, the common electrode is provided at the side of the elementsubstrate 11. In addition, the element substrate 11 is arranged at theemitting side of the display light with regard to the opposing substrate12. An upper polarization plate 18 is arranged to overlap in the uppersurface of the liquid crystal panel 10 and a lower polarization plate 17is arranged between the lower surface of the liquid crystal panel 10 andthe illumination device 8.

In the embodiment, the element substrate 11 is larger than the opposingsubstrate 12. As a result, the element substrate 11 has a protrudingsection 110 which protrudes from an edge portion of the opposingsubstrate 12 in the one side Y1 in the Y axial direction and a flexiblewiring substrate 200 is connected in the upper surface of the protrudingsection 110. The flexible wiring substrate 200 has a configuration wherea plurality of flexible wiring substrates are connected, and a controlIC (not shown) which configures the image signal supply section 270which was described with reference to FIGS. 1A and 1B and a light sourcedriving IC (not shown) which configures the light source driving section280 are mounted in the flexible wiring substrate 200.

Configuration of Illumination Device 8

FIGS. 5A and 5B are explanatory diagrams illustrating a configuration ofthe surroundings of the light source substrate 88 which is used in theillumination device 8 of the liquid crystal display device 100 accordingto the first embodiment of the invention, and FIGS. 5A and 5B are anexplanatory diagram schematically illustrating an appearance of one sidesurface 881 side of the light source substrate 88 and an explanatorydiagram schematically illustrating an appearance of the other sidesurface 882 side of the light source substrate 88. Here, theconfiguration of the light emitting element 89 and the light sourcesubstrate 88, which are arranged in the two side edge surfaces 801 and802 (the light incident sections 80 a) which oppose each other in the Yaxial direction of the light guiding plate 80, are the same.Accordingly, the light emitting element 89 and the light sourcesubstrate 88 which are arranged on the side edge surface 802 of thelight guiding plate 80 are shown in FIG. 5A and the light sourcesubstrate 88 and the like which are arranged on the side edge surface801 of the light guiding plate 80 are shown in FIG. 5B.

As shown in FIGS. 3 to 4B, the illumination device 8 is provided withthe light guiding plate 80 which is arranged to overlap with the lowersurface side of the liquid crystal panel 10 and the plurality of lightemitting elements 89 which are lined up from one edge side of the lightincident section 80 a (the one side X1 in the X axial direction) towardthe other edge side (the other side X2 in the X axial direction) by thelight emitting surface 89 a facing the light incident sections 80 a ofthe light guiding plate 80. In the embodiment, the plurality of thelight emitting elements 89 are mounted on the one surface 881 of thelight source substrate 88 which extends in the X axial direction alongthe light incident section 80 a. The light emitting elements 89 are LEDs(Light Emitting Diodes) which emits white light and emits the lightsource light as scattered light.

In the illumination device 8 of the embodiment, the two side edgesurfaces 801 and 802 which oppose each other in the Y axial directionamong the side edge surfaces 801, 802, 803, and 804 of the light guidingplate 80 are used as the light incident sections 80 a. As a result, theplurality of light emitting elements 89 are lined up toward a lightemitting surface 89 a in the two light incident sections 80 a (the sideedge surfaces 801 and 802) of the light guiding plate 80 and from oneedge side of each of the two light incident sections 80 a (the side edgesurfaces 801 and 802) toward the other edge side. In addition, two ofthe light source substrates 88 extend along the two light incidentsections 80 a (the side edge surfaces 801 and 802) and the plurality oflight emitting elements 89 are mounted on each of the one sides 881 ofthe two light source substrate 88.

In the embodiment, the light guiding plate 80 is a resin plate withtransparency which is formed from an acrylic resin, a polycarbonateresin, or the like and a reflecting sheet 187 is arranged to overlapbetween a lower surface 80 c of the light guiding plate 80 and thebottom plate section 45 of the first frame 40.

In addition, optical sheets such as the diffusing sheet 182 and theprism sheets 183 and 184 are arranged to overlap between the uppersurface (light emitting surface 80 b) of the light guiding plate 80 andthe liquid crystal panel 10. The dispersing sheet 182 is formed from asheet which is provided with a coating layer where silica particles andthe like have been dispersed in a transparent resin such as an acrylicresin, a polycarbonate resin, or the like. In the embodiment, the twoprism sheets 183 and 184 are arranged so that the ridge lines intersecteach other. As a result, directionality is applied to the illuminationlight which is emitted from the light emitting surface 80 b of the lightguiding plate 80 by the two prism sheets 183 and 184 after beingdispersed into all directions by the dispersing sheet 182 so that thereis a peak in the front direction of the liquid crystal panels 10. In thelight guiding plate 80, a dispersing pattern formed from fine indentswith a concave shape and a printing layer of a dispersing member isformed in a lower surface 80 c which is the surface on the side wherethe reflecting sheet 187 is positioned, and in the embodiment, thedensity of the dispersing pattern increases along with separation fromthe light emitting elements 89. As a result, the intensity distributionof the illumination light which is emitted from the light guiding plate80 is uniformized irrespective of separation from the light emittingelements 89. As the dispersing patter, a plurality of fine concavesections 80 e are provided in the lower surface 80 c of the lightguiding plate 80 in the embodiment.

In the bottom plate section 45 of the first frame 40, steps arepartially formed so that it is possible to secure a gap between thelower surface 80 c of the light guiding plate 80 and the first frame 40in a region which overlaps with the sides where the side edge surfaces801 and 802 which are the light incident surfaces 80 a are positioned inthe light guiding plate 80 and are curved toward the light guiding plate80. Due to this, it is possible to interpose the reflecting sheet 187and a lower plate section 61 of a light source supporting member 60 inthe gap between the lower surface 80 c of the light guiding plate 80 andthe bottom plate section 45. In addition, since a concave section isformed in the rear surface side of the first frame 40 due to that thebottom plate section 45 of the first frame 40 is partially curved towardthe light guiding plate 80, the flexible wiring substrate 200 is curvedand extends to the lower surface (rear surface) of the bottom platesection 45 of the first frame 40 and a circuit substrate 250 is arrangedin the concave section so as to be contained in the depth of the concavesection. As a result, it is possible to achieve a reduction in thethickness of the illumination device 8.

In the embodiment, the light source substrate 88 is arranged so that onesurface 881 where the light emitting elements 89 are mounted opposes thelight incident section 80 a of the light guiding plate 80. In addition,the light source substrate 88 has a configuration where a wiring patternand a land are provided with an insulation layer in the one surface 881of a metal plate 887 with a plate shape which extends along the lightincident section 80 a. The configuration is able to be realized by, forexample, a flexible wiring substrate 888 where a resin substrate layer,a wiring pattern, an insulation and protection layer, and the like arelaminated in this order being bonded to the one surface 881 of the metalplate 887. Accordingly, the land where the metal plate 887, the wiringpattern, and a chip of the light emitting elements 89 are mountedsecures electrical insulation. In the embodiment, the metal plate 887 isformed from an aluminum plate and the metal plate 887 ensures themechanical strength of the light source substrate 88 and functions as aheat releasing plate of heat which is generated from the light emittingelements 89.

As shown in FIGS. 3 to 5B, the light source supporting members 60 whichhold the light source substrate 88 are each arranged between each of theother surfaces 882 of the two light source substrates 88 and the lightsource support members 60 is held by being arranged between the firstframe 40 and the second frame 30. In the embodiment, the light sourcesupporting members 60 are metal parts with rod shapes which extend alongthe other surface 882 of the light source substrate 88 and are fixed bybeing closely adhered in a surface contact state of the entire surfaceof the other surface 882 of the light source substrate 88 and asubstrate holding surface 620 of a supporting plate section 62. Inaddition, the light source supporting member 60 has a lower platesection 61 which overlaps with the bottom plate section 45 of the firstframe 40 and the supporting plate section 62 which is configured of awall surface which protrudes upwards from an intermediate position ofthe lower plate section 61 in the width direction. In addition, thelight source supporting member 60 is provided with an upper platesection 63, which is curved to the side opposite to the side from thesupporting plate section 62 where the light guiding plate 80 ispositioned, in an upper edge side of the support plate section 62 (theside which is opposite to the lower plate section 61) and the upperplate section 63 is fixed to at least one of any of the upper platesection 55 of the third frame 50 or the upper plate sections 315 or 325of the second frame 30 using a screw or the like.

In the light source supporting member 60 in this configuration, asurface on a side of the supporting plate section 62 which is positionedon the light guiding plate 80 is the substrate holding surface 620 whichholds the light source substrate 88 and the light source substrate 88 isfixed to the substrate holding surface 620 using a screw or the like. Inthis state, the other surface 882 (metal plate 887) of the light sourcesubstrate 88 overlaps with the substrate holding surface 620 of thelight source supporting member 60. In addition, the light sourcesupporting member 60 is made of metal such as aluminum or an iron-basedmetal. As a result, the heat which is generated by the light emittingelements 89 is transferred to the light source supporting member 60 fromthe metal plate 887 of the light source substrate 88 and the heat in thelight source supporting member 60 is transferred to the first frame 40.Accordingly, it is possible to suppress increases in temperature in thelight emitting elements 89 to be low.

Configuration of Periphery of Dispersion Sheet 182

FIGS. 6A and 6B are explanatory diagrams of a main portion of the liquidcrystal display device 100 according to the first embodiment of theinvention, and FIGS. 6A and 6B are an explanatory diagram schematicallyillustrating a cross section of an edge portion of the liquid crystaldisplay device 100 and an explanatory diagram schematically illustratinga cross section of an edge portion of the dispersion sheet 182. Here,the diagrammatical representation of the lower polarization plate 17 andthe upper polarization plate 18 are not included in FIGS. 6A and 6B.

As shown in FIGS. 6A and 6B, in the liquid crystal display device 100 ofthe embodiment, the light which is emitted from the light emittingelements 89 is transmitted through the inner section of the lightguiding plate 80 after having been incident from the light incidentsection 80 a as shown by the arrow L1, is dispersed by the dispersionpattern which is formed on the lower surface 80 c of the light guidingplate 80, and is emitted as illumination light from the light emittingsurface 80 b as shown by the arrow L2. Then, after having been dispersedin all directions by the dispersing sheet 182, the illumination light isincident on the image display region 100 a of the liquid crystal panel10 after the directionality is applied so that there is a peak in thefront direction of the liquid crystal panel 10 using the two prismsheets 183 and 184 and is emitted as display light as shown by the arrowL3 after having been modulated using the liquid crystal panel 10. Theimage display region 100 a is formed at an inner edge of the frame edgelayer 120 which is formed in the opposing substrate 12.

When an image is displayed in this manner, directionality is applied tothe light, which is emitted from a periphery portion 80 g where thelight incident section 80 a is positioned in the light guiding plate 80as shown by the arrow L11 among the light which is incident in the lightguiding plate 80 from the light incident section 80 a, so that there isa peak in the front direction of the liquid crystal panel 10 using thetwo prism sheets 183 and 184 after having been dispersed in alldirections using the dispersing sheet 182 in a case where there is noreflecting surface 180, and the light reaches the frame edge layer 120without reaching the image display region 100 a and does not contributeto display. Therefore, in the embodiment, in the dispersing sheet 182(light guiding plate side of the optical sheet) which is positioned onfarthest to the light guiding plate 80 side (the side which directlyopposes the light emitting surface 80 b of the light guiding plate 80)among the plurality of optical sheets which are formed from thedispersing sheet 182 and the prism sheets 183 and 184, a reflectingsurface 180 is attached to a portion which overlaps with the peripheryportion 80 g on the side of the light guiding surface 80 where the lightincident section 80 a is positioned and the reflecting surface 180reflects the light which is incident from the side of the light guidingplate 80 toward the light guiding plate 80 side. Here, the widthdimension in the Y axial direction of the reflecting surface 180 is setto be narrower than the gap (width dimension) from the edge section ofthe liquid crystal panel 10 to the edge section of the frame edge layer120 on the image display region 100 a side.

In the embodiment, the reflecting surface 180 is attached to a surface182 b on the light guiding plate 80 side among two surfaces 182 a and182 b of the dispersing sheet 182. In addition, a reflecting layer 180 ais formed with a width dimension from the edge section of the dispersingsheet 182 to an intermediate position of the frame edge layer 120 in thewidth direction. In addition, since the two side edge surfaces 801 and802 which oppose each other in the light guiding path 80 are the lightincident sections 80 a, the reflecting surface 180 is attached to aportion in the dispersing sheet 182 which overlaps with the peripheryportions 80 g on both sides of the light guiding plate 80. That is, thereflecting surface 180 is formed in a stripe shape along both edgesections which oppose each other in the dispersing sheet 182. Here, thereflecting surface 180 may be formed with a rectangular frame shapewhich spans the entire periphery of the dispersing sheet 182.

In configuring the reflecting surface 180 in this manner, in theembodiment, the reflecting surface 180 is configured by the reflectinglayer 180 a which is laminated onto the dispersing sheet 182 and thesurface side of the reflecting layer 180 a which opposes the peripheryportion 80 g of the light guiding plate 80 is the reflecting surface180. Here, the reflecting layer 180 a is formed with a thickness whichis thinner than the thickness of the dispersing sheet 182.

As the reflecting layer 180 a, it is possible to use a white layer whichis formed from a coating film, a transcription film, a sputtering film,or a deposition film. For example, if a coating of a white coatingmaterial, transferring of a white film, or a sputtering film or adeposition film which is a white layer such as a metal oxide is used, itis possible to form the reflecting layer 180 a which is formed from awhite film. In addition, it is possible to form the white layer using awhite sheet member which is bonded to the dispersing sheet 182, forexample, a white PET (Polyethylene Terephthalate) sheet or the like.

In addition, as the reflecting layer 180 a, it is possible to use alayer which has glossiness. The layer which has glossiness is, forexample, a metal film such as an aluminum film, an aluminum alloy film,a silver film, or a silver alloy film. The layer which has glossiness isalso able to be formed as a coating film, a sputtering film, or adeposition film. In addition, it is possible to form the layer which hasglossiness using a metal sheet (a member with a sheet shape) which isbonded to the dispersing sheet 182.

Here, as shown in FIGS. 4A, 4B, and the like, in the embodiment, boththe side edge surfaces 801 and 802 of the light guiding plate 80 are thelight incident surfaces 80 a, but a configuration may be adopted whereeither of the side edge surfaces 801 or 802 is the light incidentsurface 80 a. For example, a configuration may be adopted where only theside edge surface 801 is the light incident section 80 a and the sideedge surface 802 is not the light incident surface 80 a. Even in such acase, the reflecting surface 180 may be provided on the side of the sideedge surface 802 as shown in FIG. 4B, and in this case, the widthdimension in the Y axial direction of the reflecting surface 180 whichis provided on the side of the side edge surface 802 is set to benarrower than the width dimension in the Y axial direction of thereflecting surface 180 which is provided on the side of the side edgesurface 801 as shown in FIG. 4A.

Main Effects of the Embodiment

As described above, in the liquid crystal display device 100 of theembodiment, the light which is emitted from the periphery portion 80 gof the light guiding plate 80 (the arrow L11 in FIG. 6A) does notessentially contribute to display, but in the embodiment, the reflectingsurface 180 is attached to the portion, which overlaps with theperiphery portion 80 g of the light guiding plate 80 side where thelight incident section 80 a is positioned, in the dispersing sheet 182(light guiding plate side of the optical sheet) which is positionedfarthest to the light guiding plate 80 side among the plurality ofoptical sheets which are arranged to overlap between the light guidingplate 80 and the liquid crystal panel 10. As a result, the light (thearrow L11 in FIG. 6A) which is emitted from the periphery portion 80 gof the light guiding plate 80 is returned into the light guiding plate80 by being reflected by the reflecting surface 180 as shown by thearrow L12 in FIG. 6A, and after this, is emitted as illumination lightfrom the light emitting surface 80 b while progressing within the lightguiding plate 80. In addition, since the reflecting surface 180 isattached to the dispersing sheet 182 which is positioned farthest to thelight guiding plate 80 side, the attenuation of the light which isreflected by the reflecting surface 180 until returning into the lightguiding plate 80 is small. Accordingly, according to the embodiment, theefficiency where the light which is emitted from the light emittingelements 89 (light sources) is used as illumination light is high.

In addition, since the reflecting surface 180 is attached to thedispersing sheet 182, the reflecting surface 180 is also positioned ifthe dispersing sheet 182 is positioned using the second frame 30 and thelike. Accordingly, different to the case where a reflecting member whichis a separate body is used, the number of processes when the liquidcrystal display device 100 is assembled does not increase even if thereflecting surface 180 is added.

Furthermore, it is possible to effectively perform the process ofproviding the reflecting surface 180 if there is the dispersing sheet182 compared to a case where a reflecting surface is attached to thelight guiding plate 80. For example, since the dispersing sheet 182 ismanufactured as a sheet with long sides, it is possible to form thereflecting surface 180 in a state of the dispersing sheet 182 with longsides during the manufacturing of the dispersing sheet 182 or after thedispersing sheet 182 has been manufactured, and after that, to use thedispersing sheet 182 with long sides by cutting into predetermineddimensions. Therefore, it is possible to efficiently manufacture thedispersing sheet 182 where the reflecting surface 180 is provided. Inaddition, since it is not bulky and is light compared to the lightguiding plate 80 if there is the dispersing sheet 182, it is possible toefficiently perform the process of providing the reflecting surface 180if there is the dispersing sheet 182 compared to the light guiding plate80.

In addition, the reflecting surface 180 is attached to the surface 182 bon the light guiding plate 80 side of the dispersing sheet 182. As aresult, since there is not an optical sheet between the reflectingsurface 180 and the light guiding plate 80, it is not necessary that thelight which is reflected by the reflecting surface 180 passes throughthe optical sheets when returning into the light guiding plate 80.Therefore, it is possible to suppress the attenuation of the light whichis reflected by the reflecting surface 180 until returning into thelight guiding plate 80 to be as small as possible. Therefore, it ispossible to efficiently use the light which is reflected by thereflecting surface 180 as illumination light.

Furthermore, in the forming of the reflecting surface 180 using thereflecting layer 180 a, the thickness of the reflecting layer 180 a isthinner than the thickness of the dispersing sheet 182. As a result, itis possible to prevent considerable warping of the optical sheets whenthe optical sheets of the dispersing sheet 182 and the prism sheets 183and 184 are arranged to overlap even when the reflecting layer 180 a isprovided.

Second Embodiment

FIGS. 7A and 7B are explanatory diagrams of a main portion of the liquidcrystal display device 100 according to a second embodiment of theinvention, and FIGS. 7A and 7B are an explanatory diagram schematicallyillustrating a cross section of an edge portion of the liquid crystaldisplay device 100 and an explanatory diagram schematically illustratinga cross section of an edge portion of the dispersing sheet 182. Here,since the basic configuration of the embodiment is the same as the firstembodiment, common portions have the same reference numeral attached andthe description thereof is omitted. In addition, the diagrammaticalrepresentation of the lower polarization plate 17 and the upperpolarization plate 18 is not included in FIGS. 7A and 7B.

As shown in FIGS. 7A and 7B, even in the liquid crystal display device100 of the embodiment, the reflecting surface 180 is attached to theportion, which overlaps with the periphery portion 80 g of the lightguiding plate 80, in the dispersing sheet 182 (light guiding plate sideof the optical sheet) which is positioned farthest to the light guidingplate 80 side among the plurality of optical sheets which are formedfrom the dispersing sheet 182 and the prisms sheets 183 and 184 in thesame manner as the first embodiment. The reflecting surface 180 reflectsthe light which is incident from the side of the light guiding plate 80toward the light guiding plate 80. In addition, the reflecting sheet 180is attached to the surface 182 b on the light guiding plate 80 sideamong the two surfaces 182 a and 182 b of the dispersing sheet 182 inthe same manner as the first embodiment.

In the configuring of the reflecting surface 180 in this manner, in theembodiment, the portion which overlaps with the periphery portion 80 gof the light guiding plate 80 in the surface 182 b of the dispersingsheet 182 on the light guiding plate 80 side is set as a smooth surface180 b. The boundary of the smooth surface 180 b and the air layerfunctions as the reflecting surface 180 since the refractive index ofboth is different. That is, in the embodiment, the smooth surface 180 bis set so that the roughness of the surface is small so that surfacereflectivity is increased more than the surface of the other portions ofthe dispersing sheet 182. Since the other configurations are the same asthe first embodiment, the description is not included.

Even with the liquid crystal display device 100 of the embodiment, thelight (the arrow L11 in FIG. 7A) which is emitted from the peripheryportion 80 g of the light guiding plate 80 is returned into the lightguiding plate 80 by being reflected by the reflecting surface 180 asshown by the arrow L12 in FIG. 7A, and after this, is emitted asillumination light from the light emitting surface 80 b whileprogressing within the light guiding plate 80 in the same manner as thefirst embodiment. In addition, since the reflecting surface 180 isattached to the dispersing sheet 182 which is positioned farthest to thelight guiding plate 80 side, the attenuation of the light which isreflected by the reflecting surface 180 until returning into the lightguiding plate 80 is small. Accordingly, according to the embodiment, theeffects are accomplished in the same manner as the first embodiment suchas the efficiency where the light which is emitted from the lightemitting elements 89 (light sources) is used as illumination light beinghigh.

In addition, in the embodiment, since the reflecting surface 180 isformed using the smooth surface 180 b of the dispersing sheet 182itself, it is possible to prevent considerable warping of the opticalsheets when the optical sheets such as the dispersing sheet 182 and theprism sheets 183 and 184 are arranged to overlap.

Third Embodiment

FIGS. 8A and 8B are explanatory diagrams of a main portion of the liquidcrystal display device 100 according to a third embodiment of theinvention, and FIGS. 8A and 8B are an explanatory diagram schematicallyillustrating a cross section of an edge portion of the liquid crystaldisplay device 100 and an explanatory diagram schematically illustratinga cross section of an edge portion of the dispersing sheet 182. Here,since the basic configuration of the embodiment is the same as the firstembodiment, common portions have the same reference numeral attached andthe description thereof is omitted. In addition, the diagrammaticalrepresentation of the lower polarization plate 17 and the upperpolarization plate 18 is not included in FIGS. 8A and 8E.

As shown in FIGS. 8A and 8B, even in the liquid crystal display device100 of the embodiment, the reflecting surface 180 is attached to theportion, which overlaps with the periphery portion 80 g of the lightguiding plate 80, in the dispersing sheet 182 (light guiding plate sideof the optical sheet) which is positioned farthest to the light guidingplate 80 side among the plurality of optical sheets which are formedfrom the dispersing sheet 182 and the prisms sheets 183 and 184 in thesame manner as the first embodiment. The reflecting surface 180 reflectsthe light which is incident from the side of the light guiding plate 80toward the light guiding plate 80.

In the embodiment, opposite to the first embodiment, the reflectingsurface 180 is attached to the surface 182 a (the surface on the sideopposite to the light guiding plate 80) on the prism sheet 183 sideamong the two surfaces 182 a and 182 b on the dispersing sheet 182.

In the configuring of the reflecting surface 180 in this manner, in theembodiment, the reflecting surface 180 is formed from the reflectinglayer 180 a which is formed on the dispersing sheet 182 in the samemanner as the first embodiment. Here, in the configuring of thereflecting surface 180, a smooth surface is formed in the dispersingsheet 182 itself and the smooth surface may be used as the reflectingsurface 180 in the same manner as the second embodiment.

Even with the liquid crystal display device 100 of the embodiment, thelight (the arrow L11 in FIG. 8A) which is emitted from the peripheryportion 80 g of the light guiding plate 80 is returned into the lightguiding plate 80 by being reflected by the reflecting surface 180 asshown by the arrow L12 in FIG. 8A, and after this, is emitted asillumination light from the light emitting surface 80 b whileprogressing within the light guiding plate 80 in the same manner as thefirst embodiment.

In addition, since the reflecting surface 180 is attached to thedispersing sheet 182 which is positioned farthest to the light guidingplate 80 side, the effects are accomplished in the same manner as thefirst embodiment such as the attenuation of the light which is reflectedby the reflecting surface 180 until returning into the light guidingplate 80 being small.

Furthermore, in the forming of the reflecting surface 180 using thereflecting layer 180 a, the thickness of the reflecting layer 180 a isthinner than the thickness of the dispersing sheet 182. As a result, itis possible to prevent considerable warping of the prism sheets 183 and184 when the optical sheets of the dispersing sheet 182 and the prismsheets 183 and 184 are arranged to overlap even when the reflectinglayer 180 a is provided.

Fourth Embodiment

FIGS. 9A and 9B are explanatory diagrams of a main portion of the liquidcrystal display device 100 according to a fourth embodiment of theinvention, and FIGS. 9A and 9B are an explanatory diagram schematicallyillustrating a cross section of an edge portion of the liquid crystaldisplay device 100 and an explanatory diagram schematically illustratinga cross section of an edge portion of the dispersing sheet 182. Here,since the basic configuration of the embodiment is the same as the firstembodiment, common portions have the same reference numeral attached andthe description thereof is omitted. In addition, the diagrammaticalrepresentation of the lower polarization plate 17 and the upperpolarization plate 18 is not included in FIGS. 9A and 9B.

In the first to third embodiments described above, there is aconfiguration where the one surface 881 of the light source substrate 88opposes the light incident surface 80 a of the light guiding plate 80,but as shown in FIGS. 9A and 9B, the invention may be applied to theliquid crystal display device 100 with a configuration where the onesurface 881 of the light source substrate 88 is orthogonal to the lightincident section 80 a of the light guiding plate 80. Even in thisconfiguration, it is possible to supply illumination light to the liquidcrystal panel 10 since the light emitting surfaces 89 a of the lightemitting elements 89 oppose the light incident section 80 a of the lightguiding plate 80.

Other Embodiments

In the first to fourth embodiments, both the side of the side edgesurface 801 of the light guiding plate 80 and the side of the side edgesurface 802 of the light guiding plate 80 are set as the light incidentsections 80 a, but the invention may be applied to the liquid crystaldisplay device 100 where only either of the side edge surfaces 801 or802 is the light incident section 80 a.

Example of Mounting in Electronic Apparatus

In the embodiments described above, a liquid crystal television is shownas an example as the electronic apparatus 2000 where the liquid crystaldisplay device 100 is mounted, but the liquid crystal display device 100where the invention is applied may be used in the display section of anelectronic apparatus such as a display of a personal computer, digitalsignage, a car navigation device, a mobile information terminal otherthan the liquid crystal television.

The entire disclosure of Japanese Patent Application No. 2011-157592,filed Jul. 19, 2011 is expressly incorporated by reference herein.

What is claimed is:
 1. A liquid crystal display device comprising: alight guiding plate having a plurality of edge surfaces; a plurality oflight sources each of which having a light emitting surface which facesa one edge surface of the plurality of the edge surfaces; a liquidcrystal panel including an image display region and being arranged tooverlap with the light guiding plate in a plan view; a dispersing sheetbeing disposed between the light guiding plate and the liquid crystalpanel; an optical sheet being disposed between the liquid crystal paneland the dispersing sheet; and a coating film being disposed on an uppersurface of the dispersing sheet and between the dispersing sheet and theliquid crystal panel, and between the one edge surface and the imagedisplay region in a plan view, wherein the coating film is in directcontact with the dispersing sheet.
 2. An electronic apparatuscomprising: the liquid crystal display device according to claim
 1. 3.The liquid crystal display device according to claim 1, wherein athickness of the coating film is thinner than a thickness of thedispersing sheet.
 4. The liquid crystal display device according toclaim 1, wherein the coating film is formed from a layer which is white.5. The liquid crystal display device according to claim 1, wherein thecoating film is formed from a layer which has glossiness.
 6. The liquidcrystal display device according to claim 1, wherein the coating film isformed from a transcription film, a sputtering film, a deposition film,and a member with a sheet shape.
 7. The liquid crystal display deviceaccording to claim 1, wherein the coating film is a light reflectivematerial.
 8. The liquid crystal display device according to claim 1,wherein the coating film is a white layer.
 9. The liquid crystal displaydevice according to claim 1, further comprising: a front frameoverlapping the liquid crystal panel, and the front frame have anopening which includes a plurality of edges corresponding to the imagedisplay region, wherein the coating film is disposed between the oneedge of the light guiding plate and an edge of opening which is closestto the one edge among the plurality of edges.